snap: remove one synchronize_net()

No need to wait for a rcu grace period after list insertion.

Signed-off-by: Eric Dumazet <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/802/psnap.c

···
 out:
 	spin_unlock_bh(&snap_lock);
 
-	synchronize_net();
 	return proto;
 }